public static function purge($dir)
{
if (!is_dir($dir)) {
mkdir($dir);
}
foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::CHILD_FIRST) as $entry) {
if ($entry->isDir()) {
rmdir($entry);
} else {
unlink($entry);
}
}
}